Purification of hydrocarbons



' the neutralization .of the hydrocarbon Patented d. 15, 192%..

- Arum oFrieE.

DAVID GOULD, 'OIEOORN'WELLS, PENNSYLVANIA, ASSIGNOR TO THE BARRETT COM- PANY, A. CORPORATION OF NEW JERSEY.

I PURIFICATION OF HYDROCARBONS.

No Drawing- To all whom it may concern:

Be it known that'I, Davin F. GOULD, a citizen of the United States,residing at Cornwells, in the county of Bucks and State a of Pennsylvania, have. invented certain'new and useful Impro'vements'in the Purification of "Hydrocarbons, of which the following is a specification. v

- My invention relates to the process of lo purifying hydrocarbons, such as naphthalene, fluorene, acenaphthene, etc. It relates more particularly to that part of the refining process in which the hydrocarbon is washed with sulphuric acid in order to remove certain impurities.

My co-pending application, Serial No. 442,821, filed Feb. 5, 1921, patented Jan. 9, 1923; Patent No. 1,4A1,4=-l7, describes aprocess of crystallizing a-molten hydrocarbon I after a sulphuric acid washing, and afterwards washing the crystals with water or an aqueous solution. In this process the hydrocarbon is crystallized either by cooling in a pan or similar means or by agitating with 26 hot water and gradually lowering the temperature to below the melting'point of the hydrocarbon. "The present invention is an additional"mprovement on the process in connection with-the latter step.

I have found that it is advantageous to effect the hot water "crystallization, above mentioned, in the presence of alkali more than suflicient toefiect complete neutralization of the acids remaining in the washed hydrocarbon. In practicing this, I add a slight excess over the necessary amount of caustic soda, 'or other alkali, to the vessel in which the crystallization is to be efiected and add the washed molten hydrocarbon to 10 thissolution, afterwards agitating a'nd'cooling the mixture until crystallization isjcombring about this cooling plete. I prefer to by the gradual addition of cold water al- -though other means may be used. This I crystallization in the presence of aqueous alkali takes the place of a subsequent water washing of the crystals, although such subsequent washing with water or other aqueousliquid may also be applied. In performirlilg t e alkali, if desired, may be added to the'molten hydrocarbon, although} prefer to add the hydrocarbon to tllGL,.&ll0l1,aS above doscribed, in order to .eifectegneutralization of Application filed November 3, 1922. Serial No. 598,926.

the acids in the hydrocarbon more quickly. This neutralization may or may not be preceded by washing the molten hydrocarbon with water on other aqueous solution after the sulphuric acid wash in order to remove the bulk of the acid impurities.

In carrying out this invention, molten impure naphthalene, for example, may be treated with sulphuric acid, the spent acid drawn off, and the treatment repeated as many times as may be necessary to attain the desired degree of purificatlon. The material may then be washed with hot'water a num ber of times whereupon it will be left in an acid condition due to sulphuric acid and sul-.

lization in the presence of alkali gives a somewhat more complete removal of the impurities in the hydrocarbon and at the same time makes possible the application of the process in iron apparatus without undue corrosion. i

A specific example of the manner in which my process may be applied to naphthaleneis as follows: 60,000 pounds of the molten impure naphthalene is washedby agitation with 1450 pounds of 66 B. sulphuric acid, the acid being subsequently settled and drawn ofi'. This washing may be repeated as inany times as is advisable. Following the drawing of off the last acid the molten naphthalene is washed with 750 gallons of hot water which is settled and drawn ofi". A second similar water wash is given. The naphthalene, still crystallizing agitator which contains 400 gallons of 27% caustic mixture is agitated and about 6000 gallons of cold water is run in slowly so as to cool the mixtureand cause the naphthalene to crystallize. The aqueous liquid is drained somewhat acid, is pumped molten into the soda solution. The

away from the naphthalene crystals and the crystals washed with water to remove the caustic soda and other impurities. The naphthalene is then ready for final distillation.

I claim:

1. The process of purifying hydrocarbons which comprises washing the molten hydrocarbon and crystallizing the hydrocarbon in the presence of an aqueous alkali solution.

2. The process of purifying hydrocarbons which comprises washing the molten hydrocarbon with sulphuric acid and crystallizing the hydrocarbon in the presence of an aqueous alkali solution.

3. The process of purifying naphthalene which comprises washing the molten naphthalene with sulphuric acid and crystallizing the naphthalene in the presence of an aqueous alkali solution.

thalene with sulphuric acid, drawing ofi' the I spent acid, washing the molten naphthalene with an aqueous liquid and crystallizing the naphthalene in the presence of an aqueous alkali solution.

5. The process of purifying naphthalene which comprises washing the molten naphthalene with sulphuric acid, drawing off the spent acid, washing the molten naphthalene with an aqueous liquid and crystallizing the naphthalene in the presence of caustic soda.

' DAVID F. GOULD. 3

2o 4. The process of purifying naphthalene which comprises washing the molten naph- 

